Java/JPA/Hibernate 一对一和一对多的实体映射

Question

Need help in entity mapping. I have Debtor entity and it has one to many mapping with Addresses entity. I also have different address types and Debtor should have one to one mapping with each address type. Each address type is a subclass of Addresses. While running test case I am getting below error

"Provided id of the wrong type for class inquiry.entity.CurrentAddress. Expected: class java.lang.Integer, got class java.lang.String; nested exception is java.lang.IllegalArgumentException:"

Can anyone help, how to map the entities.

@Entity
@Table(name="debtors")
public class Debtor{

    @Id
    @Column(name = "id" , length = 127)
    private String id;

    @OneToOne
    @JoinColumn(name = "id", referencedColumnName = "parent_id")
    private CurrentAddressStd currAddrStd;

    @OneToOne
    @JoinColumn(name = "id", referencedColumnName = "parent_id")
    private CurrentAddress currAddr;

    @OneToMany
    @JoinColumn(name = "parent_id")
    private List<Addresses> addresses;

    

}

@Entity
@Table(name="addresses")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(discriminatorType = DiscriminatorType.STRING, name = "type")
public class Addresses{
    @Id
    @GeneratedValue(strategy= GenerationType.SEQUENCE)
    private int id;

@Any(metaColumn = @Column(name = "parent_type"))
    @AnyMetaDef(idType = "string", metaType = "string",
            metaValues = {
                    @MetaValue(targetEntity = Contact.class, value = "Contact"),
                    @MetaValue(targetEntity = Debtors.class, value = "Debtor"),
                    
            })

    @JoinColumn(name = "parent_id")
    public Object parentItem;
}

@Entity
@DiscriminatorValue("CurrAddrStd")
public class CurrentAddressStd extends Addresses{

}

public interface AddressesRepository extends CrudRepository<Addresses,Integer> {
}

Answer 1

In your Debtor class you have this:

@OneToOne
@JoinColumn(name = "id", referencedColumnName = "parent_id")
private CurrentAddress currAddr;

The @OneToOne is telling Hibernate that the foreign key is found in the Debtor class itself, with column name "id", which is a String . In your CurrentAddress class, which is mapped back to Addresses , you have a @Id field, which is an int . Hibernate can't match an int Primary Key with a String Foreign Key, which results in the error you are getting.

Taken from here for the definition of the name attribute of the JoinColumn annotation:

(Optional) The name of the foreign key column. The table in which it is found depends upon the context.

If the join is for a OneToOne or ManyToOne mapping using a foreign key mapping strategy, the foreign key column is in the table of the source entity or embeddable.